Net-A-Porter's AR window shop concept came out back in September, but as Ad Age and others are reporting today, a new effort to launch the brand's Karl by Karl Lagerfield collection includes a new app that users can download before trekking to pop-up storefronts in Paris, New York, London, Munich and Sydney to view the collection via their iPads and iPhones.

Here's the deal: Scan a product image for the chance to win the product - or buy them - and maybe even receive free goodies at the store.

I have to admit that part of the concept is a little lost on me here.

On the one hand, as Adverblog points out, this demonstrates the power of merging online and physical retailing. I mean, I'm not a fashionista (as anyone who knows me will tell you), so the excitement this has clearly elicited with these women is a little lost on me.

What is exciting is that it clearly does have this impact on what appears to be a particularly avid customer base straight out of central casting.

Because let's face it: This all seems like a lot of trouble. Why shop at an online retailer if that same retailer is having you download an app and go track down a pop-up store on a busy city street for stuff you should be able to buy (or win) directly from the website?

And yet it's working - so hats off (AR or otherwise) to Net-a-Porter for an innovative initiative.